In conventional cylinder blocks for automobile internal combustion engines, a cylinder block made of aluminum alloy in which a liner made of cast iron is casted in is mainstream as a bore surface thereof. From the viewpoint of reducing weight of engine parts however, development is in progress for a cylinder block of a type that casts in liners made of aluminum instead of liners made of cast iron or for a monoblock made of aluminum alloy that has totally eliminated the liners made of cast iron.
However, liners made of aluminum and monoblocks made of aluminum alloy are problematic in their abrasion resistance and scuffing resistance characteristics. Although there are cases in which plating such as nickel plating is carried out thereto, this cannot be said as sufficient in relation to the abrasion resistance and scuffing resistance characteristics.
Moreover, as an alternative to the above means, also employed is a measure to improve abrasion resistance and scuffing resistance characteristics by spraying on spray powder by plasma flame to a cylinder bore inner surface to form a sprayed coating. For example, in the invention described in Patent Literature 1, the abrasion resistance and scuffing resistance characteristics with respect to a piston ring and piston are improved by spraying iron-based alloy powder on a bore surface of a cylinder block for an engine.